The invention relates to a device for counting objects in a surveillance region, comprising a counting module, wherein the counting module includes an object counter that is increased by one counting value on average when one of the objects, as the object to be counted, completely passes through a counting section in a counting direction, and including at least one surveillance camera for recording the surveillance region, wherein the surveillance camera is designed to output an image data stream of the surveillance region, and including an extraction module designed to extract moving image regions in a current image from the image data flow, and wherein the moving image regions can represent the objects or segments thereof. The invention also relates to a method for counting objects, and to a computer program.
For operators of public or commercial buildings, such as supermarkets, it is interesting to determine how many persons, in particular potential buyers, enter the building each day. In other areas as well, entering and exiting moving objects are counted: It is typical, for example, to count cars that drive into and out of a parking garage.
Depending on the area of application, various devices for counting have become common: In the case of the parking garage, for instance, it is possible to record the cars using contactless inductance measurement. In supermarkets, on the other hand, buyers can be counted using simple light barriers that trigger a counter when they are interrupted. In the case of the aforementioned procedures, however, only individual moving objects can be detected, and these measurement methods cannot be used to determine the direction of the moving object. A further weakness of the light-barrier method is that the light barrier can be blocked by stationary objects.
It likewise appears possible to count moving objects using video surveillance systems. Video surveillance systems of that type typically comprise a plurality of cameras that are directed to a surveillance region, wherein the image data streams from the cameras are combined in a surveillance center to be monitored manually or in an automated manner. It is possible, for instance, to track moving objects for a certain period of time, wherein the number of tracked objects represents a count of these moving objects. The video surveillance systems function at their best when the moving objects can be well delineated from each other. In contrast, for video-based surveillance methods, this means that the objects in the camera image should not overlap or be situated too closely to each other. Erroneous evaluations can occur when scenes are densely populated in particular since moving objects can overlap as described above.
Publication DE 10 2006 053 286 A1, which is the closest prior art, describes a method for detecting image regions of salient motion, wherein a current optical flow field in an image sequence is calculated and compared with a reference flow field that includes the main directions of flow of image regions of the depicted scene, wherein a counter-flow field having motion vectors of image regions of salient motion is formed from image regions of the scene, the motion vectors of which are not oriented in the main flow directions.